/usr/lib/x86_64-linux-gnu/libstk.so is in libstk0-dev 4.5.2+dfsg-5build1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libstk-4.5.0.so
/usr/lib/x86_64-linux-gnu/libstk-4.5.0.so